Continuous Effect of Radial Resection Margin on Recurrence and Survival in Rectal Cancer Patients Who Receive Preoperative Chemoradiation and Curative Surgery: A Multicenter Retrospective Analysis

Abstract Purpose Resection margin status is a well-known prognostic factor after curative surgery in colorectal cancer. However, proper length and significance of circumferential resection margin (CRM) and distal resection margin (DRM) in rectal cancer patients who received neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision (TME) has not been clearly determined yet. Methods and materials A total of 1476 rectal cancer patients staging cT3-4N0-2M0 were analyzed. All patients received radiation dose of 50.4 Gy in 28 fractions with concurrent 5-fluorouracil or capecitabine. TME was performed 4 to 8 weeks after radiotherapy. Results The recurrence-free survival (RFS) at 5 years showed a significant difference between three groups; patients with CRM ≤ 1mm, CRM 1.1-5mm, and CRM > 5mm (46.2% vs. 68.6% vs. 77.5%, P P P P P =0.192) than those with CRM > 5mm. DRM (≤ 5 vs. > 5mm) did not show any significant difference in cumulative incidence of locoregional recurrence ( P =0.310) and distant metastasis ( P =0.926). Conclusion The rectal cancer patients with CRM ≤ 1mm is a high-risk group with the lowest RFS. Patients with CRM 1.1-5mm may be at intermediate risk with moderately increased distant recurrence. DRM was not significantly associated with the RFS in rectal cancer after neoadjuvant CRT and TME.